The nursery industry commonly utilizes thin-walled plastic pots which contain one or more plants. An array of pots are assembled in a plastic pot flat which allows a number of filled pots to be transported, stored, and sold as a unit. The end user, for example a home gardner, may then remove individual pots from the flat for final disposition of the plant contained therein.
The pots and flats are commonly stackable thermoformed plastic articles, and are supplied to the nursery stacked within cartons.
Conventionally, the pots are arrayed within the flats manually, typically using seasonal labor.
The nestability of the pots and flats advantageously allows large numbers of articles to be conveniently stored in a relatively small volume. The ability to store large numbers of containers at relatively high-bulk density is essential to the economic shipping and storage of the lightweight, plastic containers.
Two problems are associated with using lightweight, nested containers in conjunction with automated machinery. The first is associated with placing the nested containers so that as each container is denested it is presented to the automated handling apparatus at a constant datum. The second problem is associated with ensuring that only one container is removed from the nested stack at a time.
Apparatus for handling nested plastic containers are known which utilize a magazine either gravity- or spring-fed which presents a container to be denested at a constant datum relative to the denesting apparatus. In this type of apparatus, the containers or cups are held in the magazine by a rigid lip or resilient fingers which prevent more than one container from being removed from the magazine at a time. The containers, cups, or trays are normally pulled from the magazine by means of one or more resilient suction cups which are in communication with a vacuum pump. The resilient cups form an air tight seal with one or more surfaces of the container so that atmospheric pressure forces the container against the suction cup firmly attaching it to the gripper as long as the suction cups are in communication with the source of vacuum. The gripper, by means of the suction cups, grips the container and pulls it from the container magazine, in the process either deforming the container to pass by the rigid lip or deforming the resilient retaining fingers. The containers are then either translated or rotated relative to their stacked location and released from the suction cups by connecting the suction cups to a source of atmospheric or superatmospheric pressure. The use of suction cups connected to a vacuum source for gripping the containers is advantageously used in connection with a suction sensitive switch in pneumatic communication with the suction cups so that when the suction cups are sealed against the surfaces of the containers, the suction sensitive switch may initiate the movement of the gripper which removes the container from the nested stack and positions it for further processing.
Increased labor costs in the nursery business has developed a need for automated machinery to reduce the cost of producing transplants and potted plants.
Conventional denesting apparatus which require the use of magazines which require the individual hand loading of the magazines are not readily adaptable to varying numbers of containers of different sizes. Further, conventional destacking apparatus are not well adapted to placing a full array of pots in a flat.
An apparatus is needed for destacking from cartons an array of pots and for further destacking a tray or flat and for depositing the array of pots in the plant flat in a generally automatic fashion.